Door assemblies of the type specified have been previously proposed which enable a sliding door to be swung outwardly and downwardly and so that rollers at the top of the swingable door also move outwardly by way of guide means (on a support slide rail for the rollers) co-operable with cam means on the door. The swingable door may be raised and lowered, whilst the cam means rides on the guide means, by a lever operated mechanism mounted on the swingable door and/or on a part of the assembly adjacent the swingable door. The lever operated mechanism usually involves part of the assembly adjacent the bottom of the swingable door acting as a support for part of the mechanism whilst the swingable door is moved from the closed position to the second position and vice versa.
Such assemblies are designed for vehicles because the maximum outer dimensions and therefore the width of the vehicle are regulated by law and yet there is a need to have full access to the interior of the vehicle through one or more side walls of the vehicle for unloading or loading. It is often unnecessary to open the whole side at once and it is sufficient if this can be done in stages.
Various problems exist in the design of sliding door assemblies of the type specified and the reliability of a particular design has to be weighed against the convenience and cost of manufacture as well as the ease of operation and simplicity of the system. Particular problems exist in the design of the rails of the assembly along which the swingable door can slide as well as in the operating mechanism and means employed to swing the swingable door out of the closed position.